Traditionalist Catholicism is a movement that emphasizes beliefs, practices, customs, traditions, liturgical forms, devotions and presentations of teaching associated with the Catholic Church before the Second Vatican Council (1962–1965). Traditionalist Catholics particularly emphasize the Tridentine Mass, the Roman Rite liturgy largely replaced in general use by the post-Second Vatican Council Mass of Paul VI.

Marcel François Marie Joseph Lefebvre was a French Catholic archbishop who influenced modern traditional Catholicism. In 1970, five years after the close of the Second Vatican Council, he founded the Society of Saint Pius X (SSPX), a community to train seminarians in the traditional manner, in the village of Écône, Switzerland. In 1988, Pope John Paul II declared that Archbishop Lefebvre had "incurred the grave penalty of excommunication envisaged by ecclesiastical law" for consecrating four bishops against the pope's express prohibition but, according to Lefebvre, in reliance on an "agreement given by the Holy See ... for the consecration of one bishop."